Sangamo BioSciences Announces Publication of Preclinical Data Demonstrating Gene Correction in SCID-X1 Human Hematopoietic Stem Cells

RICHMOND, Calif., May 28, 2014 /PRNewswire/ -- Sangamo BioSciences, Inc. (Nasdaq: SGMO) announced today the publication in Nature of data demonstrating efficient zinc finger nuclease (ZFN)-mediated, targeted gene insertion that resulted in correction of the genetic defect in stem cells from an individual with X-linked severe combined immunodeficiency (SCID-X1). Importantly, the study demonstrates that the treatment successfully targets a class of hematopoietic stem cells (HSCs) that are responsible for the long term repopulation of the bone marrow following transplant. The data support the clinical translation of this approach for SCID-X1, other immunodeficiencies and monogenic diseases.

"The ability to accomplish targeted integration of a therapeutic gene into HSCs represents a major step forward in the quest for more precise and safe gene therapies," stated Luigi Naldini, M.D., Ph.D., Director, San Raffaele Telethon Institute for Gene Therapy (TIGET) and a senior author on the paper. "We used ZFNs to promote insertion of a corrective DNA sequence into the IL2RG gene in HSCs derived from either cord blood or bone marrow. This strategy enables correction of the inherited functional defect of the gene while at the same time restoring its expression under physiological control. This work should open a path to the development of safer and potentially curative treatments for SCID-X1 and, conceivably, other genetic disorders."

The study, entitled "Targeted genome editing in human repopulating haematopoietic stem cells," was conducted at TIGET by a team of scientists led by Dr. Naldini in collaboration with Sangamo scientists, and was published as an Advance Online Publication in Nature http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13420.html.

Researchers capitalized on the fact that ZFN-mediated genome editing requires only a transient expression of the ZFNs to effect a permanent change in the genome.  They used messenger RNA and electroporation to deliver the ZFNs and a non-integrating vector, an Integrase Defective Lentiviral Vector (IDLV), to provide a corrective therapeutic DNA sequence, a so-called "donor template," to human stem cells. This delivery approach, in combination with modified culture conditions for the cells, increased the efficiency of gene transfer and targeted integration particularly in more primitive longer-lasting stem cells, to levels that can be used therapeutically to potentially treat a range of monogenic diseases.

The study, which included testing the proposed gene correction strategy in vitro in HSCs derived from the bone marrow of a symptomatic four-month-old SCID-X1 patient, demonstrated the functional reconstitution of the IL2RG gene in the lymphoid progeny of corrected HSCs in vivo.

"Sangamo's ZFN gene-editing platform provides precise permanent targeted integration of therapeutic genes in contrast to conventional integrating vector approaches which insert genes randomly," stated Philip Gregory, D. Phil., Sangamo's senior vice president, research and chief scientific officer, and a co-author of the study. "This work demonstrates efficient targeted gene insertion in long-term repopulating HSCs which support multilineage differentiation in to all cells of the blood. These data support the application of ZFN-mediated gene modification across a range of monogenic diseases."

About Sangamo
Sangamo BioSciences, Inc. is focused on Engineering Genetic Cures^TM for monogenic and infectious diseases by deploying its novel DNA-binding protein technology platform in therapeutic gene regulation and genome editing. The Company has ongoing Phase 2 clinical trials to evaluate the safety and efficacy of a novel ZFP Therapeutic^® for the treatment of HIV/AIDS (SB-728-T) and NGF-AAV for Alzheimer's disease (CERE-110). Sangamo's other therapeutic programs are focused on monogenic and rare diseases.  The company has formed a strategic collaboration with Shire International GmbH to develop therapeutics for hemophilia, Huntington's disease and other monogenic diseases, and with Biogen Idec for hemoglobinopathies, such as sickle cell disease and beta-thalassemia. It has also established strategic partnerships with companies in non-therapeutic applications of its technology, including Dow AgroSciences and Sigma-Aldrich Corporation. For more information about Sangamo, visit the Company's website at www.sangamo.com.

ZFP Therapeutic® is a registered trademark of Sangamo BioSciences, Inc.

This press release may contain forward-looking statements based on Sangamo's current expectations. These forward-looking statements include, without limitation, references to the research and development of novel ZFP TFs and ZFNs and their applications in the treatment of SCID-X1, other immunodeficiencies and monogenic diseases, partnerships with collaborators and potential clinical trials of ZFP Therapeutics based on preclinical studies.  Actual results may differ materially from these forward-looking statements due to a number of factors, including uncertainties relating to the initiation and completion of our clinical trials, whether the clinical trials will validate and support the tolerability and efficacy of ZFNs, technological challenges, Sangamo's ability to develop commercially viable products and technological developments by our competitors. For a more detailed discussion of these and other risks, please see Sangamo's SEC filings, including the risk factors described in its Annual Report on Form 10-K and its most recent Quarterly Report on Form 10-Q. Sangamo BioSciences, Inc. assumes no obligation to update the forward-looking information contained in this press release.

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SOURCE Sangamo BioSciences, Inc.